Bishop and pawn endings

Bishop and pawn endgames come in two distinctly different variants. If the opposing bishops go on the same color of square, the mobility of the bishops is a crucial factor. A bad bishop is one that is hemmed in by pawns of its own color, and has the burden of defending them.

The diagram on the right, from Molnar-Nagy, Hungary 1966, illustrates the concepts of good bishop versus bad bishop, opposition, zugzwang, and outside passed pawn. White wins with 1.e6! (vacating e5 for his king) Bxe6 2.Bc2! (threatening Bxg6) 2...Bf7 3.Be4! (threatening Bxc6) Be8 4.Ke5! Seizing the opposition (i.e. the kings are two orthogonal squares apart, with the other player on move) and placing Black in zugzwang—he must either move his king, allowing White's king to penetrate, or his bishop, allowing a decisive incursion by White's bishop. 4...Bd7 5.Bxg6!

Bishop and pawn versus bishop on the same color

Two rules given by Luigi Centurini in the 19th century apply:

The game is a draw if the defending king can reach any square in front of the pawn that is opposite in color to the squares the bishops travel on.

If the defending king is behind the pawn and the attacking king is near the pawn, the defender can draw only if his king is attacking the pawn, he has the opposition, and his bishop can move on two diagonals that each have at least two squares available (other than the square it is on) (Fine & Benko 2003:152). This is the case for central pawns and the bishop pawn whose promotion square is not the same color as the bishop (Fine & Benko 2003:154).

The position in the second diagram shows a winning position for White, although it requires accurate play. A knight pawn always wins if the defending bishop only has one long diagonal available (Fine & Benko 2003:155–56).

The diagram on the right, from Molnar-Nagy, Hungary 1966, illustrates the concepts of good bishop versus bad bishop, opposition, zugzwang, and outside passed pawn. White wins with 1.e6! (vacating e5 for his king) Bxe6 2.Bc2! (threatening Bxg6) 2...Bf7 3.Be4! (threatening Bxc6) Be8 4.Ke5! Seizing the opposition (i.e. the kings are two orthogonal squares apart, with the other player on move) and placing Black in zugzwang—he must either move his king, allowing White's king to penetrate, or his bishop, allowing a decisive incursion by White's bishop. 4...Bd7 5.Bxg6!

This position was reached in a game from the 1965 Candidates Tournament between Lajos Portisch and former World Champion Mikhail Tal. White must defend accurately and utilize reciprocal zugzwang. Often he has only one or two moves that avoid a losing position. Black was unable to make any progress and the game was drawn on move 83 (Nunn 1995:169).

Bishops on opposite colors

The opposite-colored bishops endgame is a chess endgame in which each side has a single bishop, but the bishops reside on opposite-colored squares on the chessboard, thus cannot attack or block each other. Without other pieces (but with pawns) these endings are notorious for their tendency to result in a draw. These are the most difficult endings in which to convert a small material advantage to a win. With additional pieces, the stronger side has more chances to win, but not as many as if the bishops were on the same color.

Many players in a poor position have saved themselves from a loss by trading down to such an endgame. They are often drawn even when one side has an advantage of two or even three pawns, since the weaker side can create a blockade on the squares on which his bishop operates.

Edmar Mednis gives two principles for endgames with bishops on opposite colors:

If a player is down material he should look for drawing chances in an endgame with only the bishops and pawns.

With major pieces (queen or rook) on the board, having bishops on opposite colors favors the side with an attack (Mednis 1990:75).